The present invention relates to a closure element for the sterile closure of connections, and in particular to the closure of connections with filter modules for dialysis, hemofiltration or ultrafiltration.
In the production of filter modules for dialysis, it is necessary to sterilize the filter modules after the actual manufacturing process and also to protect the filter modules from external influences, such as the penetration of microorganisms or dirt. One method of sterilizing filter modules is the so-called in-line sterilization, where the interior areas of the filter module are cleaned, although the outside is not sterilized. Because open contact of the connections of the filter module during or after the sterilization step must absolutely be avoided, the filter module must be sealed in such a way that no contamination or soiling of the interior of the filter module can occur during sterilization or after removal from the sterilization device.
European Patent 352,540 describes a generic closure element consisting of two parts, with the first part of the closure element being attached to the connection of the filter module or the dialyzer, while the second part of the closure element is accommodated in a receptacle space of the first closure element part. The device is arranged movably between an open position and a closed position in this receptacle space. Thus, in the open position, passage of the sterilization medium and sterilization of all sealing surfaces and guidance surfaces can be achieved. In the closed position, reliable sealing of the dialyzer can be achieved. Although such a closure element guarantees reliable sealing of the filter module, it has the disadvantage of having a relatively complex structure.
The present invention is an improvement upon a generic closure element having a simple design that can reliably ensure a sterile closure.
The closure element includes a wall having a slit-shaped indentation that closes automatically, and when closed forms a germ-proof closure. There are also fastening means that are adjacent to the wall, so the closure element can be attached to a connection by these fastening means. Such a closure element according to this invention has a simple design and provides a reliable and sterile seal of a medical object, such as a filter module, during and after sterilization, due to the automatically closing slit-shaped indentation. When a suitable connecting element such as a connection of a sterilization device or of a dialysis machine is inserted, the slit-shaped indentation in the closure element according to this invention is opened to fit the shape of the connecting element.
When the connecting element according to this invention is removed from the closure element, after sterilization or treatment, the slit-shaped indentation closes automatically, thus preventing contamination of the sterilized area as well as leakage from the item sealed with the closure element.
In an especially advantageous embodiment, the closure element has an essentially cylindrical shape, and the fastening means are formed by the cylindrical surface and the slit-shaped indentation, arranged on one of the end faces of the cylinder. The closure element forms a germ-proof connection to the medical item by means of the cylindrical surface. Such a cap-like design of the closure element has the advantage that the fluid supplied and removed flows along a simple linear path in a passage through the closure element. The development of dead zones can thus be effectively prevented by an appropriate arrangement of the slit-shaped indentation. This design also prevents the mixing of different fluids, such as mixtures containing different active ingredients or medicines, that pass through the closure element.
Another embodiment of the present invention provides for a symmetrical closure element design. Such a design not only simplifies the manufacture of the closure element, but also permits simple handling as well as simple attachment and use of the closure element on the corresponding connection of a filter module.
A preferred embodiment of the present invention provides for the slit-shaped indentation to have the shape of a cross or a star. This shape permits a very good flexibility and adaptation to connections of various shapes and various diameters, in comparison with a simple linear design of the indentation. Another wall having an opening for the passage of a fluid may be provided opposite to the wall with the indentation. In one example, the middle of the indentation may be aligned with the opening.
Another embodiment of this invention provides for the surface of the other wall extending around the opening to extend in a plane essentially perpendicular to the joining direction of the connecting element of the invention. In this case, the closure element according to this invention additionally provides a tight connection of the connecting element, for example between a dialysis machine and the filter module. A seal can be achieved by the connecting element having its end face sealably placed inside the opening of the other wall.
It is especially advantageous if the closure element according to this invention is a single piece, to provide advantages in the manufacturing process.
It is also especially advantageous if the wall with the indentation, and more preferably advantageous if the entire closure element, is made of plastic. In this manner, the flexibility and elasticity of the closure element can be varied widely through the choice of a suitable plastic. In addition, compatibility with the fluid used or with a mixture containing various active ingredients can be achieved through the choice of the plastic. The use of plastic for the wall of the closure element having the indentation, or for the entire closure element, also has the advantage that a simple and cost-effective manufacturing process can produce a variety of different embodiments and designs of the closure element. It is especially advantageous if the plastic is a silicone plastic.
An advantageous embodiment includes a wall with the slit-shaped indentation in the closure element that has a spring element acting in the radial direction. This yields the advantage that radial stress forces are reduced over the transverse direction in the path of the spring element. This results in a slit-shaped indentation in the wall having improved sealing properties.
In another embodiment of the present invention, the spring element can be formed by recesses that alternate or are individually placed on the top and/or bottom sides of the wall. The recesses may be partially circular.
It is especially advantageous if no spring element is provided in the areas of the wall extending in the longitudinal direction of the slit-shaped indentation. This design increases the radial force acting in the direction of the slit, which yields an especially tight closure of the slit-shaped indentation.
Another embodiment of the present invention provides for the slit-shaped indentation in the closure element to form a germ-proof closure resisting up to a pressure difference of about xc2x10.25 bar.
The present invention also concerns the use of a closure element for the sterile closure of connections of medical items. In a preferred embodiment, the medical item is a filter module for dialysis, hemofiltration or ultrafiltration, with the closure element being used for in-line sterilization of the filter module.
Another embodiment of the present invention provides for fastening means of the closure element that permit the closure element to be placed on projecting connections, or inserted into bushing-like connections.
The present invention also concerns a medical item with one or more connections for supplying and/or removing a fluid, with at least one connection being provided with a closure element according to this invention. The medical item may be a filter module for dialysis, hemofiltration or ultrafiltration.
It is especially advantageous if the closure element is designed in such a way that its inside surface is connected by a germ-proof connection to the outer surface of a projecting connection. It is also advantageous if the outside surface of the closure element is connected by a germ-proof connection to the inside surface of a bushing-shaped connection.
Another embodiment of the present invention provides for at least two connections of the medical item having a closure element according to this invention.